Copper-zinc alloys



2,144,993 PATENT OFFICE COPPER-ZINC ALLOYS Wolf Johannes Miiller and .Morlta Niessner,

Vienna, Austria, assign'ors to Oesterreichlsche Dynamit Nobel Aktiengesellschaft, Vienna, Austria, a firm of Austria No Drawing. Original application June 29, 1935, Serial No. 29,102. Divided and this application June 16, 1937, Serial N0. 148,506. In Austria July 21, 1934 3 Claims.

It is known that gamma-brass, that is to say copper zinc alloys with a copper content of about 31-40%, 1. e., alloys which are characterized by a low copper content, are more resistant to cor- 5 rosion than the brass alloys of the alpha and alpha and betaregion with for instance 68-72 percent and more of copper, i. e., a higher copper content. The technical employment of gammaalloys poor in copper is however impossible, since these alloys are extremely hard and brittle and are consequently not machinable.

From such alloys, as is described in our prior Patents No. 2,006,598 and 2,006,599 it has been disclosed that it is possible, by the addition of a few percent of a metal soluble in gamma-brass or alloyable therewith, such as nickel or, with more advantage cobalt, preferably by a simultaneousaddition of nickel and cobalt to obtain alloys, which possess the good resistance to corrosion of gamma-alloys poor in copper, but are also capable of being worked up, that is to say can be treated with machine tools and can alsobe rolled hot. Such alloys with an addition of instance pure copper-zinc alloys with a minimum content of nickel of approximately 7-8% or oi. cobalt of approximately 5-6% have extremely good technical properties, and when cobalt and nickel are used simultaneously it is possible with a much smaller cobalt content to obtain the same efiects as with the use of cobalt alone. Consequently alloys that are deficient in copper, even those most deficient, can be made utilizable for industrial purposes or as constructional material for the production of articles, ii the copper-zinc alloys are alloyed with cobalt, nickel or the like individually or in mixture.

The present invention is based on the ascertained fact that such copper zinc alloys, containing between 30 and 45% of copper and between 3 and 12% of cobalt and/or nickel, can have their properties substantially improved when containing also between 4 and 15 of manganese and at least one of the metals of the following group:

Percent Iron Up to 1.8 Aluminium Upto 1.5 Silver Up to 2.0 Chromium Up to 3.0

Tin Up to 2.0 Lead 'Up to 0.3 Selenium Up to 0,6 Tellurium Up to 0.6

60 but in no greater amounts than are soluble in approximately 3-10% of cobalt, nickel or the like individually or in mixture, that is to say for the solid solution and the zinc constituting substantially the remainder.

It has been ascertained that such alloys are suitable for cold working, including cold rolling, pressing and drawing and at the same time have a high resistance to corrosion.

in carrying out the invention, the manganese content should be smaller in the case of alloys of higher copper content than in the case of alloys of lower copper content. The higher the manganese content the more suitable is the alloy for cold working a rising addition of manganese up to about 10% leading to an approximately proportional improvement in the cold working properties.

By the addition of the metals of .the group: iron, aluminium, silver, chromium, tin, lead, selenium and tellurium the workability in the cold, the color and other properties of the alloys are favourably influenced as compared with such alloys containing only copper zinc, nickel and/or cobalt and manganese as are subject of our copending application Ser. No. 29,102 filed June 29, 1935, from which the present application is divided out.

Thus an enhanced workability in the cold can be imparted to the alloys of the invention, by the addition of suitable amounts of one or more of the elements iron, lead, tin, selenium and tellurium within the limits hereinbefore set forth while their corrosion resistance can be enhanced by the addition of one or more of themetals aluminium, chromium and tin within the limits hereinbefore set forth.

It is easy to ascertain empirically, the amount of each element that will produce the most favorable efiect.

A suitable alloy in accordance with the invention is one containing between 30 and 45% of copper, between 3 and 12% of cobalt and/or nickel, between 4 and 15% of manganese and between 0.5 and 1.5% of iron.

Theaddition of 'up to 0.3% of phosphorus to the hereindescribed alloys is advantageous since it very considerably improves the fineness of structure of the alloys.

By means of the additions according to the invention therange of the solid solution can also be increased, to some extent, beyond that of the binary alloy, and alloys with a somewhat higher copper content which however must be substantially less than 45%, which come within the beta+- gamma range in the binary alloy, can also be converted into a state corresponding to gamma brass and rendered suitable for applications, such as cold rolling or drawing,- from which they are otherwise excluded on account of their cope per content.

The following is a typical according to the invention:

example of an alloy Percent Cu 36 Ni 6 Co 2 Mn 10 Fe 1.2 Zn Remainder What we claim is: 1. A corrosion resistant alloy mechanically workable in the cold having the following composition:

Percent Copper 35 to 45 Cobalt and nickel 3 to 12 Manganese 4 to 15 Iron Upto 1.5 Zinc- Remainder WOLF JOHANNES M'ULLER. MORITZ NIESSNER. 

